1. Field of the Invention
The present invention relates to a production process of a color filter, and particularly to a production process of a color filter making use of an ink-jet printing method. The color filters produced in the present invention are used in the field of color liquid crystal display devices and the like.
The present invention also relates to a production process of a liquid crystal display device.
2. Related Background Art
With the advancement of personal computers, particularly, portable personal computers in recent years, the demand for liquid crystal display devices, particularly, color liquid crystal display devices increases. It is however necessary to greatly reduce the cost of the color liquid crystal display devices for further spreading them. There is a demand for reduction in the cost of color filters particularly given much weight from the viewpoint of the cost.
As a process for producing a color filter at low cost, it is proposed to form light-screening black matrices on a glass base and apply inks toward spaces between the black matrices using an ink-jet printer, thereby coloring portions of the base corresponding to the spaces. With respect to this process, materials hard to wet with inks and easy to repel the inks are investigated as materials for black matrices in order to successfully fill the inks in space areas between the black matrices, which correspond to respective pixels.
For example, Japanese Patent Application Laid-Open No. 7-35917 proposes a process in which a material for black matrices having a contact angle with inks of at least 20.degree. is used to form black matrices, and the inks are ejected toward space areas between the black matrices. In Japanese Patent Application Laid-Open No. 7-35915, it is proposed to use a material having a contact angle with water of at least 40.degree. as a material for black matrices. In Japanese Patent Application Laid-Open No. 6-347637, it is proposed to adjust critical surface tensions of a base surface, inks and a black matrix surface so as to be the base surface&gt;the inks&gt;the black matrix surface, and to preset their critical surface tensions in such a manner that the black matrix surface is lower than 35 dyn/cm, the base surface is not lower than 35 dyn/cm, and the inks are different by at least 5 dyn/cm from both the base surface and the black matrix surface. In all these examples, it is proposed to contain a fluorine compound or a silicon compound in materials for the black matrices to impart a high water repellency to the materials.
Besides, Japanese Patent Application Laid-Open No. 4-121702 proposes a process for forming banks having a solvophilicity opposite to a base and charging inks between banks. However, detailed description as to materials is not made.
When a fluorine compound or a silicon compound, which is a water repellent, is mixed into a material for black matrices like these examples, however, the water repellent in the material for black matrices is evaporated upon post baking, which is a final step for forming a black matrix pattern, to thinly attach to the surface of a glass base corresponding to the spaces between black matrices. On the other hand, even when no water repellent is added, low molecular organic substances contained in the material for black matrices are evaporated to attach to the glass surface likewise. In each case, the glass surface comes to exhibit water repellency, which causes a problem that when inks are applied to portions of the glass base corresponding to the spaces between black matrices, said portions being to serve as pixels, the inks are prevented from attaching thereto.